This invention relates to a novel process for recovering copper from copper sulfide concentrates.
The main objects of this invention are to improve the efficiency of processes for recovering copper from copper sulfide concentrates; to reduce the overall cost of this production; and to reduce or eliminate thermal, air, water and chemical pollutions.
A significant novel feature of this invention is the use of the copper sulfide concentrate's sulfur atom, to prepare higher sulfur content polysulfides of sodium or potassium by fusing concentrate and lower sulfur polysulfides under vacuum conditions. Powdered elemental copper is recovered during this process. Thermal decomposition of the higher (sulfur content) polysulfides produces lower sulfur content polysulfides which in turn are used to produce additional higher (sulfur content) polysulfides and additional copper.
Because the literature in this field reported that fused sodium or potassium hydroxide when mixed with copper metal, produce first the oxide and, subsequently, carbonate complexes under atomospheric conditions, this invention is all the more unpredictable and surprising.